The ad appears to be legitimate — according to Chrome Unboxed, clicking on the "Shop now" button took the user to the Pixelbook page of the Google Store.

Like last year's Pixelbook, the device appears to be a convertible laptop-tablet hybrid with a foldable screen and compatible stylus, called the Pixelbook Pen. The original Pixelbook cost $999, plus an additional $99 for the pen.